Joe Staley’s right knee injury is not as serious as originally feared, and the Pro Bowl left tackle is preparing to be on the field Sunday when the 49ers face the Seattle Seahawks at Candlestick Park.

Staley said on Friday morning on his weekly radio show on 95.7 The Game that he is optimistic he’ll be able to play against the NFC West-leading Seahawks after returning to practice on Thursday.

“It feels a lot better,” Staley said. “The MCL sprain was not a severe one. But also it was one of those issues in the game where they put me down, wanted me to get an MRI and thought I’d done some damage to it. But all the results came back pretty positive.

“The week’s been going well. We’ll see how it responds day to day, but yesterday was a good day. I was out there on the practice field, did some individuals stuff, and hopefully I’ll do more stuff today.”

Staley sustained the injury on the 49ers’ sixth offensive play Sunday against the St. Louis Rams. He was immediately ruled out for the remainder of the game. The 49ers originally felt the injury would keep Staley sidelined for at least one game.

Staley’s injury is less severe than the MCL sprain that left guard Mike Iupati sustained on Nov. 17 against the New Orleans Saints. Iupati has not practice since going down with the injury.

Alex Boone shifted from right guard to left tackle to take over for Staley against the Rams. Second-year player Joe Looney filled in at guard. Veteran Adam Snyder is in line to make his third consecutive start at left guard for Iupati.